Oracle Essentials: Oracle9i, Oracle8i and Oracle8, Second Edition

Oracle Advanced Queuing

Messaging technology has existed for quite some time and is common in OLTP applications. Typical messaging technologies provide a reliable transport layer for shipping messages from one machine to another over a network. Oracle8 introduced Advanced Queuing (AQ) as an integrated database service.

Oracle AQ provides the benefits of simple messaging products but adds the value of database-resident queues. The information in message queues represents critical business events and should be stored in a reliable, scalable, secure, and recoverable place. Placing the queues in the database extends the core benefits of a database to the queues themselves.

The data that flows through queues represents the ebb and flow of business activity. Analyzing the types and volumes of message traffic can help to identify how different business functions are operating and interacting and this, in turn, can provide valuable insights into the operation of your business. Oracle AQ supports the notion of message warehousing, in which the content and details of the queues can be queried and analyzed because they’re already in the database. Oracle can dequeue messages but can leave historical data in the queues for subsequent analysis.

Applications can enqueue and dequeue messages as part of a transaction or as a separate event that occurs as soon as the specific enqueue or dequeue statement is issued. Queue actions included in the scope of a transaction are committed or rolled back ...